London - Tottenham manager Antonio Conte said he has quickly realised the level of his squad is "not so high" after an embarrassing 2-1 loss to Slovenian minnows NS Mura in the Europa Conference League.
Spurs will now likely have to beat Rennes at home in their final group game to avoid crashing out of Europe's third-tier competition.
And they can no longer catch Rennes at the top of the group meaning they would progress to the last 32, while the group winners are parachuted into the last 16.
Harry Kane started as one of just two players to be retained by Conte from Sunday's 2-1 win over Leeds in the Premier League, which had appeared to launch Conte's reign.
"The level of the Tottenham is not so high."— B/R Football (@brfootball) November 25, 2021
Antonio Conte went in 😳 pic.twitter.com/8iRfJfG0tR
However, the Italian was given an early lesson into the strength of his squad with an embarrassing night in Maribor against a club founded just nine years ago.
"After three weeks I am starting to understand the situation. It is not simple," said Conte. "At this moment the level at Tottenham is not so high.
"I must be honest and tell you that after three-and-a-half weeks, I am starting to understand the situation. I can tell you that the situation is not simple."
Conte has won a league title at each of his previous three clubs during spells at Juventus, Chelsea and Inter Milan.
His arrival has sparked hopes of a return to the Champions League next season via a top-four finish in the Premier League.
But he warned he will need time to lift standards around the club.
"Someone (might) think that a new coach arrives and Conte won in the past and then I am a magician. But the only magic I can do is to work," he added.
"To bring work and work to improve, to bring my methods, my ideas of football. But we have to understand that we need time."
Tomi Horvat put the hosts into a shock lead before Ryan Sessegnon's red card left Tottenham a man down for the final hour.
Kane restored parity 18 minutes from time, but even the introduction of five first-team regulars off the bench in the second half could not prevent Amadej Marosa's stunning stoppage time winner.